This paper describes the recently updated realization of the harmonized cubic metre for natural gas. It is a procedure based on an intercomparison, that combines the mutually independent traceability chains of four primary laboratories in the field of high-pressure gas flow measurement. The reference value, also called harmonized cubic metre, is the weighted average of at least two laboratories with weighing factors that are inversely proportional to the squared uncertainties of the calibration results. This results in lower uncertainties for the laboratories as long as the stochastic contributions (Type A) to the overall measurement uncertainties are significantly smaller than the uncertainties arising from the traceability chain (Type B). This condition is fulfilled in practice as traceability uncertainties are at least a factor ten greater than the other uncertainty sources. When evaluating the data of intercomparisons, curve fitting is used for the representation of the calibration data. A polynomial equation of maximum four degrees, expressed in the logarithm of the flow Reynolds number, proves to be the optimum choice for fitting the calibration curve of the turbine gasmeters.